Orientador: Prof. Dr. Jesuí Vergílio Visentainer

 Data da Defesa: 13/02/2017



INTRODUCTION: Fish is a food of excellent nutritional value, featuring high biological assets in protein, vitamins, especially A and D, and a rich lipid fraction in unsaturated fatty acids and low cholesterol. Lipids of marine fish species are generally characterized by low levels of linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (LNA, 18:3n-3) coupled to high levels of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), due to high PUFA contents in some species of marine phytoplankton contained in their diet. Eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids are two of the most important n-3 LC-PUFA with beneficial effects on cardiovascular health and a safeguard against chronic inflammatory diseases such as arthritis, psoriasis and asthma. Since they reduce the occurrence of several types of cancer and improve the visual function, the oil of these fish is a healthy choice in human diet. AIMS: Current analysis assesses the lipid contents and composition of fatty acids in marine fish. The composition of fatty acids, mainly omega-3, in samples of salmon fillets stored in different ways was evaluated. Further, the lipid and nutritional profiles in fourteen species of marine fish captured on the coast of Fortaleza, Brazil, were compared. MATERIALS AND METHODS: Four distinct samples of salmon in different conservation methods (fresh salmon, frozen salmon, water-conserved canned salmon and long-stored frozen salmon) were purchased on the local market in Maringá PR Brazil, in July 2014, and fourteen marine species were acquired on the coast of Fortaleza, Brazil, in March 2015. The quantification of total lipids was gravimetrically measured after extraction following the Bligh and Dyer method. Composition of fatty acids was determined by gas chromatography and results underwent analysis of variance (ANOVA) at 5% significance level and principal component analysis. RESULTS AND DISCUSSION: High lipid contents, between 9.71% and 12.86%, were reported in fresh salmon, frozen salmon, water-conserved canned salmon and long-stored frozen salmon. All samples had higher levels of monounsaturated fatty acids, between 363.69 mg g-1 and 425.30 mg g-1 total lipids, followed by polyunsaturated fatty acids (294.46 mg g-1 - 342.45 mg g-1 of total lipids) and saturated fatty acids (203.32 mg g-1 - 223.17 mg g-1 of total lipids). The analysis of the principal component (PCA) allowed the separation of 5 groups of fish using the active parameter SFA (185.62 - 405.65 mg g-1 of total lipids), MUFA (148.77 - 387.98 mg g-1 of total lipid), PUFA (160.27 - 372.64 mg g1 of total lipid), n-6 (31.88 - 225.1 mg g-1 of total lipids), n-3 (69.83 - 270.62 mg g-1 of total lipids) and the n-6/n-3 ratio (0.12 - 1.68) for the fourteen samples of marine fish from the Fortaleza coast. In assessing the nutritional quality of lipids, all samples showed n-6/n-3, thrombogenicity index (IT) and hypocholesterolemic/hypercholesterolemic fatty acids ratios (HH) favorable for food consumption. However, serra did not have recommended levels when index PUFA/SFA was evaluated. CONCLUSIONS: Salmon fillets, submitted to different forms of preservation, showed no significant difference in the composition of fatty acids, particularly omega-3. All samples proved to be good sources of EPA and DHA, omega-3 fatty acids. The marine fish of the Ceará coast were divided into five groups, using the principal component 9 analysis (PCA) and the active parameter SFA, MUFA, PUFA, n-6, n-3 and n-6/n-3. Lipid content, fatty acid composition and nutritional profile demonstrated that the studied species are of good nutritional quality. All samples proved to be good sources of EPA and DHA, omega-3 family fatty acids. Keywords: fatty acids, marine fish, omega-3, total lipids.


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